1. Field of the Invention
The present invention relates, in general, to a dielectric ceramic composition for high frequencies and, more particularly, to a dielectric ceramic composition of a ZrO.sub.2 -TiO.sub.2 -SnO.sub.2 system which exhibits superior electrical quality factor Q, dielectric constant k and temperature coefficient of resonant frequency .tau..sub.f in high frequency regions. The present invention also relates to a method for preparing such dielectric ceramic composition.
2. Description of Prior Art
Conventionally, various kinds of dielectric ceramics are widely used for the materials of a dielectric resonator, a global positioning system, and the like. Recent trends to use higher frequencies in microwave systems have demanded for dielectric ceramic compositions with better electrical properties, such as improved quality factor Q, dielectric constant k and stable temperature coefficient of resonant frequency .tau..sub.f.
Among conventional dielectric magnetic compositions for high frequencies, one suggested in U.S. Pat. No. 4,665,041 has been known to be superior in quality factor Q and dielectric constant k. The dielectric ceramic compositions of supra patent is composed of a main component of a TiO.sub.2 -ZrO.sub.2 -SnO.sub.2 system and additives comprising ZnO, NiO, and one selected from Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, WO.sub.3 and Sb.sub.2 O.sub.5. However, this composition has disadvantages in that its dielectric constant is only about 35, even though its Q value is considerably improved. Another problem involved in this patent lies in that the production cost is high and it is difficult to control the precise production process therefor, since the dielectric composition of this patent consists of too many materials.